Lightweight concrete containing aggregates of cement-bonded foamed polystyrene, procedure of making the same and building structures made from this lightweight concrete

ABSTRACT

The invention concerns the field of a lightweight building structure produced by using a mortar containing foamed polystyrene and cement and a method for the production. It includes at least one layer of prefabricated foam concrete panel ( 60 ) affixed to a reinforcing frame structure ( 40 ) interspaces between elements of the reinforcing frame structure ( 40 ) are at least partially filled with a mortar ( 10, 12, 14, 16 ) providing a first surface contacting said foam concrete panel ( 60 ), said mortar ( 10, 12, 14, 16 ) comprising granules of 0.5-10 mm size produced by grinding a pressed foamed concrete that has been allowed to mature, 50-200 kg of unbound, anhydrous cement, and 150-300 l of water added before application per 1 m 3  of ground material, respectively.

THE FIELD OF THE INVENTION

The invention concerns the field of the construction industry andrelates to a mortar for buildings containing polystyrene and cement, amethod for the production of such a mortar as well as buildingstructures produced by the use of such a mortar.

BACKGROUND OF THE INVENTION

For the production of building structures having good thermal and soundcontrol properties, mortars containing foamed polystyrene, cement andwater are used, which are formed into building units either at the siteof the construction or in a factory producing building materials. Suchmortar is explained in the specification of GB 1 498 383.

Building units are produced from mortar containing polystyrene foam insuch a manner that the mortar is poured into a mould, pressed, and ifnecessary, heat treated for instance under pressure, then when theappropriate solidity is achieved, it is taken out of the mould and isallowed to stand in order to minimise the contraction tendency of suchconcrete containing polystyrene foam, hereinafter referred to as foamconcrete. After a prescribed standing time, the building units soproduced are formed into the desired size and form.

Such processing cannot be carried out at the site of constructionbecause there the mortar cannot be pressed, heat treated and be allowedto stand. If such mortar is poured into e.g. the permanent formworkduring construction, problems may arise due to contraction.

The objective is to create such a mortar for buildings which can beapplied on site, the contraction of which is small and has good soundand thermal insulation properties. Another objective is to create such amortar for buildings from which building structures and structureelements suitable to bear weight can be created.

A further objective is to create lightweight building structures withgood thermal and sound insulation properties by using such mortar.

In order to achieve the set objectives, a mortar has been created whichcontains ground material made by grinding foam concrete that has alreadycontracted and been allowed to mature and contains cement added thereto;water is added to this mixture upon application. Of course, the groundmaterial, the cement and the water may be mixed at the same time tooupon application.

The mortar so produced this way sets quickly, has a very good thermalconductivity coefficient, which is only 30-40% higher than agood-quality prefabricated foam concrete building unit.

In the course of the method for producing the mortar according to theinvention, already set and contracted foam concrete is ground intogranules no larger than 10 mm in size, and the 50-150 kg of cement and80-200 l of water are added to this. For the sake of the processabilityof the mortar, the cement-water ratio may differ from the ratio usuallyapplied in concrete mortars, it is generally higher than in the latter.

The mortar according to the invention can be produced at the site ofconstruction because the necessary grinder can be transported easily andmakes the reuse of waste generated at the construction site possible. Ifthe amount of waste generated on site is not enough, such groundmaterial or waste suitable for grinding can be obtained from a factoryproducing foam concrete products. The ground material and the requiredcement and water can be poured into a mortar making device, a mortarpump, which forwards the wet mortar to the place of applicationsubsequent to mixing.

If using a quantity of cement higher than the prescribed amount themortar produced may still be used but simultaneously with the increasedsolidity achievable by this, its thermal and sound insulation propertiesdeteriorate and a tendency for contraction may arise as well.

The mortar produced with the prescribed quantities and properly appliedis not solid but it is step resistant, therefore its surfaces exposed toload and abrasion must be protected by an appropriate layer.

By using the mortar according to the invention, a building structure hasbeen provided, which includes at least one layer of prefabricated foamconcrete panel attached to a reinforcing frame structure, and the spacebetween the elements of the reinforcing frame structure is filled atleast partially with the mortar according to the invention, the firstsurface of which contacts the foam concrete panel.

The building structure according to the invention may be also formed asa floor/ceiling structure where the reinforcing frame structure containsa load bearing beam placed in the plane of the floor/ceiling, a foamconcrete panel fixed to the beam from below and mortar according to theinvention applied in between and above the load bearing beams. Thefloor/ceiling structure may be horizontal, in which case it includeshorizontally arranged load bearing beams of I, C or U profiles, andpreferably there is a load-distributing grate placed above the loadbearing beams in the mortar.

The building structure according to the invention may include aprotecting layer spread over the mortar and if necessary, flooring (80)placed thereon.

In the version of the building structure according to the inventionwhere it is formed as a floor/ceiling structure, the panel of thefloor/ceiling structure is angled below 75° from the horizontal.

In the version of the building structure according to the inventionwhere it is formed as a standing wall element includes a first and asecond layer of foam concrete panel fixed oppositely to the reinforcingframe structure, which layers constitute a finable permanent formworkwith one another and with the frame structure, and the interspacebetween the foam concrete panels (and the frame structure is filled withthe mortar according to the invention. In the version of the buildingstructure according to the invention where it is formed as a standingwall element, a surface finish or hard crust is formed on the freesurface of the foam concrete panels opposite the one facing the mortar.One of the surfaces of the building structure is preferably constitutedof a board made of foam concrete attached to a frame structure. Theinterspaces of the frame structure are filled with the mortar accordingto the invention.

So in the version of the building structure according to the inventionwhere it is formed as a standing wall, a foam concrete board, panel isattached to both sides of the frame structure and these panelsconstitute a permanent formwork for the mortar according to theinvention filled into the interspaces of the frame structure.

If the building structure according to the invention is a floor/ceilingstructure, then the foam concrete panel constituting the permanentframework is fixed to its frame structure from below. In case of a loadbearing floor/ceiling structure, preferably there is a load-distributinggrate fixed to the frame structure and in order to achieve appropriatesound insulation, this load-distributing grate is covered with a layerof the mortar according to the invention of at least 3 cm but preferablyof 5 cm. After 24 hours, typically a protecting layer, an estrich layermay be applied to this layer, which protecting layer may be then coveredwith appropriate covering-If the building structure according to theinvention is formed as a roof structure in a place where it is exposedto neither loading nor abrasion, and no load-distributing grate and noprotecting layer is necessary.

If the building structure according to the invention is formed to bearroof covering, the elements for fixing the outer shell of the roof, e.g.laths, wood-blocks, may be embedded in the mortar.

The building structure according to the invention can be created veryquickly; it is very light and has excellent thermal and sound insulationproperties. Its further advantage is that the frame structure does notstand freely, in case of fire, the foam concrete panels protect theframe structure from quick warming. Of course, this requires the use offoam concrete that incombustible in itself.

Another advantage is that after filling in, the mortar protects theelements of the frame structure from deformation caused by loading; theelements of the frame structure, with special regard to its ranges underpressure, are practically not exposed to distortion.

The invention will be explained below with reference to exemplaryembodiments shown in the drawings wherein

FIG. 1 is the horizontal plane section of the exterior load bearing wallstructure created with the use of the mortar according to the invention,

FIG. 2 is the section drawing of the load bearing floor/ceilingstructure transversal to the beams placed therein,

FIG. 3 is the schematic section view of the joint of the interior loadbearing wall and the floor/ceiling.

FIG. 4 is the section drawing of the roof shell including an inclinedfloor/ceiling structure created with the application of the mortaraccording to the invention.

FIG. 1 shows the horizontal plane section of the exterior load bearingwall, which borders the building to the outside, created with the use ofthe mortar according to the invention. This load bearing wall is createdso that a 40 frame structure is built at first either of timber of metalprofiles with appropriate corrosion protection. In this case, the figureshows the vertical 41 posts of the 40 frame structure, on which 41 posts12-cm-thick 30 foam concrete panels are affixed from the inside and15-cm-thick 20 foam concrete panels are affixed from the outside. The 42fixing elements may be plastic screws or snap-in fixing elements whosepressing surface is large enough to hold the 20, 30 foam concrete panelswithout damage. Discs, small-holed washers or similar elements may beused to distribute pressure as necessary. In order to avoid thermalbridges and acoustic transmission paths, especially in case of 42 fixingelements made of metal, the 42 fixing elements are placed into theindentations formed in the surface of 20, 30 foam concrete panels. Aftermounting, 10 mortar is poured into the interspace between the 41 postsby means of a concrete pump, plastering machine, or other similarequipment suitable for this purpose, or by manual force. The density ofthe 10 mortar is relatively low, therefore the 20, 30 foam concretepanels are capable to bear the pressure of the filled-in 10 mortar andconstitute a permanent formwork. Any excess amount of water in the 10mortar can leak out through the slits of the 20, 30 foam concretepanels. The hardening time of the 10 mortar is approximately 2 days.Considering that the surface of the 20, 30 foam concrete panels is notsufficiently abrasion-proof, solid, at least the exterior 20 foamconcrete panel must be provided with a hard crust, the structure whereofmay be formed in a manner similar to the case of exterior thermalinsulation covering made with polystyrene boards. The interior 30 foamconcrete panel requires a less strong surface finish, e.g. glass-fibrewallpaper applied after gypsum plastering, which then may be furtherworked on as desired.

It should be noted that after hardening, the 10 mortar distributes theload to the two 20, 30 foam concrete panels, and this is what makestheir application in a load bearing wall structure possible. Without theapplication of the invention, they are not even suitable for bearingwind pressure. However, the 10 mortar makes the wall structures formedsolid to such extent that they may also be used to create the exteriorload bearing walls of multi-storeyed buildings.

FIG. 2 shows the cross section of a load bearing floor/ceilingstructure. In this case, the 40 frame structure is constituted ofI-section 44 beams, and 60 foam concrete panels are fixed to such 44beams from below by means of 42 fixing elements. A 90 load-distributinggrate is affixed to the top of the 44 beam, which 90 load-distributinggrate may be e.g. a 5×5 cm mesh concrete-reinforcing steel mat made of5-mm-diameter steel wire. After such fixing is carried out, theinterspace between the 44 beams constituting the 40 frame structure isfilled with the 14 mortar. In order to realise the sound proofingquality of the mortar according to the invention, the formation ofacoustic transmission paths in the floor/ceiling structure from top todown must be avoided. To this end, the 14 mortar is poured in to a levelhigher than that of the 90 load-distributing grate and thus the 14mortar will cover the 90 load-distributing grate, preferably in a 3-5 cmthick layer. On the top of this, two 3-cm-thick high-strength coats,composition floor (estrich) layers are applied, which may be covered asdesired.

1 m³ of dry ground foam concrete (granule size: may be approximatelybetween 1 mm and 10 mm) is mixed with 200 litres of water and 100 kg ofcement (type: A-P 32,5R 350 trass Portland cement 20 though it will bindwith any other cement of less good quality) is added. This will resultin a consistence similar to earth-damp concrete. Then it is poured tothe floor/ceiling structure by hand or a machine, according to the orderof layers indicated on FIG. 2. Thereby the polystyrene foam concretecreates a complete filling between the adjacent I-section 44 beams sothey cannot wrench because it is held by the bolted-on 60 foam concretepanel from below, the filled-in 14 mortar in between, and also by the0.5 mm thick 90 load-distributing grate from above. The 14 mortar ispoured to a level 4-5 cm higher than the 90 load-distributing grate andthe 44 beam, it is compacted by means of a vibrating poker and astraight plane surface is created. Then, after the time required forhardening expires, a 4-5 cm thick concrete or estrich layer is pouredthereon as a protective layer. Then it is covered with ceramics, wood orother finishing material.

The weight of the floor/ceiling structure created this way can becalculated as follows:

The weight of 1 m³ foam concrete is between 200 and 230 kg, the weightof the added cement is 100 kg.

Estrich: 60 kg/m²-3 cm thick.

Steel: 10 kg/m².

From the weight of the water only the amount bound by the cement shouldbe taken into account.

Thus, the weight of a 38 cm thick floor/ceiling structure isapproximately 225 kg/m².

It should be noted that compared to a traditional concrete floor/ceilingstructure, weight by surface can be reduced to its one-fifth by applyingthe invention. Moreover, it dries and can be covered within 48 hours. Onthe other hand, the full drying (hardening) time of traditional concretefloor/ceiling structures is 28 days and can be covered only thereafter.

Interior load bearing walls can also be built on the floor/ceilingstructure created by using the mortar according to the invention. The 40frame structure of the horizontal floor/ceiling indicated only by areference sign and the 40 frame structure of the load bearing wall alsoindicated symbolically by a reference sign are mounted to one another.The 60 foam concrete panels constituting the lower permanent formwork ofthe horizontal floor/ceiling structure and the 50 foam concrete panelsof the vertical load bearing wall are fixed to the 40 frame structure by42 fixing elements. The horizontal floor/ceiling structure is createdafter the lower vertical load bearing walls are completed, then the 50foam concrete panels of the vertical load bearing walls of the nextlevel are mounted. Then the horizontal floor/ceiling structure is filledwith the 14 mortar according to the invention, 24-48 hours later ahigh-strength estrich layer is applied, and then the interspace betweenthe 50 foam concrete panels located above is filled with the 12 mortaraccording to the invention.

FIG. 4 shows a 45° degree roofshell structure created by using themortar according to the invention. In this case the 40 frame structureis constituted of sloping beams or 46 I-beams substituting the slopingbeams, which are indicated by only a dotted line at the top of thefigure and may be made of galvanized? steel. At first, the framestructure is assembled, then 60 foam concrete panels are attached to itslower side by means of 42 fixing elements. 48 distance pieces are fixedto the top of the 46 I-beams, which 48 distance pieces may be woodblocks. Then the interspaces of the 40 frame structure is filled withthe 16 mortar according to the invention and the mortar is evened at thetop level of the 48 distance pieces. The consistence of the mortaraccording to the invention is such that it may be used up to an angle of75-80° In case of a steeper angle, there is a risk of slumping of themortar during application.

After a hardening time of approximately 2 days, a 72 underlay is placedon the surface, which underlay is a foil with controlled vapourpermeability traditionally used for making roofs in the constructionindustry. The foil is fixed by the 74 brandering attached to the 48distance pieces. Further 76 distance pieces may be mounted on the top ofthe 74 brandering at the same time or in a separate working phase, andthe 78 roof battens holding 92 roof tiles are fixed thereon. By using 76distance pieces and by the right selection of their proper size, theventilation of the roof can be improved.

Although the invention is explained with reference to its preferableembodiments, it is obvious to the professional with average expertise inthe field that various modifications and alternatives may be realised.The objective of the following claims is to extend to such modificationsand alternatives.

1-10. (canceled)
 11. A lightweight building structure produced by usinga mortar containing foamed polystyrene and cement, the lightweightbuilding structure comprising at least one layer of prefabricated foamconcrete panel affixed to a reinforcing frame structure interspacesbetween elements of the reinforcing frame structure are at leastpartially filled with a mortar providing a first surface contacting saidfoam concrete panel, said mortar comprising granules of 0.5-10 mm sizeproduced by grinding a pressed foamed concrete that has been allowed tomature, 50-200 kg of unbound, anhydrous cement, and 150-300 l of wateradded before application per 1 m³ of ground material, respectively. 12.The building structure according to claim 11, wherein the buildingstructure is formed as a standing wall element including a first andsecond layer of prefabricated foam concrete panels attached to oppositesides of the reinforcing frame structure said foam concrete panelstogether with said reinforcing frame structure constitute a permanentformwork defining an interspace that may be filled with the mortar, andthe interspace between the foam concrete panels and the frame structureis filled with said mortar.
 13. The building structure according toclaim 11, wherein the building structure is formed as a floor/ceilingstructure where the reinforcing frame structure includes load bearingbeams placed in the plane of the floor/ceiling structure, a foamconcrete panel fixed to the beams from below, and said mortar is appliedbetween and over the load bearing beams.
 14. The building structureaccording to claim 13, wherein said floor/ceiling structure ishorizontal and includes horizontally arranged load bearing beamsselected from I, C or U profiles.
 15. The building structure accordingto claim 14, further comprising a load-distributing grate placed in themortar above the load bearing beams.
 16. The building structureaccording to claim 14, further comprising a protective layer spread overthe mortar and a flooring placed onto said protective layer ifnecessary.
 17. The building structure according to claim 13, wherein thepanel of the floor/ceiling structure is angled less than 75° to thehorizontal.
 18. The building structure according to any of claim 11,wherein a surface finish or hard crust is formed on a free surface ofsaid foam concrete panels opposite a surface facing said mortar.
 19. Amethod for the production of the lightweight building structureaccording to claim 11, comprising providing a frame structure havinginterspaces; fixing a panel to the frame structure; filling at leastpartially said interspaces; wherein said panel comprise a hardened foamconcrete panel and said at least partial filling of said interspaces iscarried out by filling in a mortar comprising granules of 0.5-10 mm sizeproduced by grinding a pressed foamed concrete that has been allowed tomature, 50-200 kg of unbound, anhydrous cement, and 150-300 l of wateradded before application per 1 m³ of ground material, respectively. 20.The method according to claim 19, wherein providing a permanent formworkdefining an interspace by fixing a first and second layer of foamconcrete panels to opposite sides of said reinforcing frame structure,then filing said interspace defined by said permanent formwork with saidmortar.
 21. The building structure according to claim 14, furthercomprising a protective layer spread over the mortar and a flooringplaced onto said protective layer if necessary.
 22. The buildingstructure according to any of claim 12, wherein a surface finish or hardcrust is formed on a free surface of said foam concrete panels oppositea surface facing said mortar.
 23. The building structure according toany of claim 13, wherein a surface finish or hard crust is formed on afree surface of said foam concrete panels opposite a surface facing saidmortar.
 24. The building structure according to any of claim 14, whereina surface finish or hard crust is formed on a free surface of said foamconcrete panels opposite a surface facing said mortar.
 25. The buildingstructure according to any of claim 15, wherein a surface finish or hardcrust is formed on a free surface of said foam concrete panels oppositea surface facing said mortar.
 26. The building structure according toany of claim 16, wherein a surface finish or hard crust is formed on afree surface of said foam concrete panels opposite a surface facing saidmortar.
 27. The building structure according to any of claim 17, whereina surface finish or hard crust is formed on a free surface of said foamconcrete panels opposite a surface facing said mortar.